There is growing evidence that lifestyle factors might affect the health of individuals by affecting telomere length (TL). The objective of this review was to show the importance of telomeres in aging and to find out lifestyle factors that might affect health. Recent research findings show that TL can only allow an estimate of the aging rate and can be regarded as an important risk marker for age-related pathologies and mortality. Recent studies indicate that telomere length, which can be affected by different lifestyle factors, might affect the pace of aging and onset of various diseases. Telomere length shortens by aging. Shortening of telomeres is associated with increased incidence of diseases such as diabetes and cardiovascular diseases. The rate of telomere shortening might be either increased or decreased by different lifestyle factors. Choice of diet and activities can reduce the rate of telomere shortening, leading to delayed onset of age-associated diseases and increased lifespan. In this review, we discussed the role of telomeres in aging. Different lifestyle factors such as smoking and diet which can affect telomeres was discussed.